linux系统初始化脚本

ln -s /usr/share/zoneinfo/Asia/Shanghai /etc/localtime
if ! crontab -l |grep ntpdate &>/dev/null ; then
(echo “* 1 * * * ntpdate time.windows.com >/dev/null 2>&1”;crontab -l) |crontab
fi

禁用selinux

sed -i ‘/SELINUX/{s/permissive/disabled/}’ /etc/selinux/config

关闭防火墙

if egrep “7.[0-9]” /etc/redhat-release &>/dev/null; then
systemctl stop firewalld
systemctl disable firewalld
elif egrep “6.[0-9]” /etc/redhat-release &>/dev/null; then
service iptables stop
chkconfig iptables off
fi

历史命令显示操作时间

if ! grep HISTTIMEFORMAT /etc/bashrc; then
echo ‘export HISTTIMEFORMAT="%F %T whoami "’ >> /etc/bashrc
fi

SSH超时时间

if ! grep “TMOUT=600” /etc/profile &>/dev/null; then
echo “export TMOUT=600” >> /etc/profile
fi

禁止root远程登录

sed -i ‘s/#PermitRootLogin yes/PermitRootLogin no/’ /etc/ssh/sshd_config

禁止定时任务向发送邮件

sed -i ‘s/^MAILTO=root/MAILTO=""/’ /etc/crontab

设置最大打开文件数

if ! grep “* soft nofile 65535” /etc/security/limits.conf &>/dev/null; then
cat >> /etc/security/limits.conf << EOF
* soft nofile 65535
* hard nofile 65535
EOF
fi

系统内核优化

cat >> /etc/sysctl.conf << EOF
net.ipv4.tcp_syncookies = 1
net.ipv4.tcp_max_tw_buckets = 20480
net.ipv4.tcp_max_syn_backlog = 20480
net.core.netdev_max_backlog = 262144
net.ipv4.tcp_fin_timeout = 20
EOF